Apparatus for the cold-bending of pipes

ABSTRACT

A pipe bending apparatus including an anvil of a desired radius and a hammer ram having spaced hammer elements spaced from one another to have a bending radius larger than the radius of the anvil. The pipe is adapted to be incrementally fed through the apparatus between hammering actions.

United States Patent Bergner [451 June 6,1972

[54] APPARATUS FOR THE COLD-BENDING OF PIPES [72] Inventor: Siegfried Bergner, Munich, Germany [73] Assignee: Paweck AG, Chur, Switzerland [22] Filed: Aug. 27, 1969 [21 Appl. No.: 853,243

[52] US. Cl ..72/166, 72/389 [51] Int. Cl. ..B2ld 7/06, B21d 31/06 [58] Field of Search ..72/374, 376, 375, 396, 369,

[56] References Cited UNITED STATES PATENTS 2,373,822 4/1945 Geppelt ..72/413X 2,516,372 7/l950 Cross 72/369 X 2,942,643 6/1960 Pucci et a1. ..72/375 X 2,966,934 1/1961 Huet ...72/41 3 X 3,429,157 2/1969 Huth... 72/465 X 3,499,303 3/1970 Gregg 72/473 X Primary Examiner-A.ndrew R. Juhasz AttorneyWatson, Cole, Grindle & Watson 57 ABSTRACT A pipe bending apparatus including an anvil of a desired radius and a hammer ram having spaced hammer elements spaced from one another to have a bending radius larger than the radius of the anvil. The pipe is adapted to be incrementally fed through the apparatus between hammering actions.

8 Claims, 5 Drawing Figures PATENTEDJUH 6|972 3,667,269

SHEET 10F 2 I71 van for x9069 med Beryner PATENTEDJun 6 I972 SHEET 2 OF 2 I77 ania/ L8 OZ Bergwek APPARATUS FOR THE COLD-BENDING F PIPES The invention relates to a process and apparatus for the cold bending of pipes.

From the German Pat. No. 1,009,460, a machine for the cold bending of pipes has become known with a bending shape for a total bending angle of above 180 which can be shifted in a straight line and in which, on both sides of the path of movement, revolvable supports have been arranged. The periphery of the supports having an annular groove developed with a corresponding cross section for the reception of the peripheral part of the pipe left open by the groove of the bending shape, and the rotational axes of the supports are arranged eccentrically as compared to the annular groove.

This structure requires a very high power supply to carry out the cold bending of pipes once in the direction of the pressure, secondly in the rotational direction of the bearing rollers, and finally for the support of these rollers. With this known arrangement, furthen'nore, it is not possible to bend a pipe in its cold state to 360 into a complete circle.

From the German Pat. No. 1,048,462, a bending device for pipes has, furthermore, become known where as a rest between the supports, a flexible countershape has been provided which encompasses the peripheral cross section of the workpiece that is to be shaped into an outside arch. In the case of this device, too, pressure and tractive forces are required which must constantly act upon the shape that is to be bent until the desired bending has been achieved. Furthermore, in this case, too, it will be necessary to use a separate shape for every desired bending, depending on the radius.

It is an object of the invention to eliminate these and other disadvantages, in which process for the cold bending of pipes, the pressure and/or the counterparts and counter pressure are exerted by hammering. This is accomplished by a continuous simultaneous hammering at least two parts of the pipe arranged at a distance from each other on both sides of a counterpressure support whereby the movement of the hammers takes place in the plane of bending. At the same time, plane of bending, signifies that plane in which the previously straight fibers or grain of the material worked on will still lie even after the bending. Contrary to the prejudice of the ex perts which is extant even today, namely that with the process of hammering, a deformation in the sense of the change of a cross section is considered practical experience with the process according to the invention has proved that this led to time and energy and unexpectedly satisfactory results in the case of the cold bending of pipes.

In a further development of the process, the proposal is now made that during the hammering process, the pipe that is to be bent, be shifted on the countershape in a longitudinal direction that is to say, about perpendicular to the direction of movement of the hammers and that this shifting of the pipe can take place evenly or unevenly as well as repeatedly back and forth. This process will permit corrections in the bending radius even during the operating process and the complete in dependence of the temporal course of a feed mechanism and, therefore, also the manual feed.

Furthermore, the process according to the invention provides that the pipe that is to be bent be turned radially during the hammering process and that the material of the shapes, for example, a shock resistant plastic, be attached to the pipe material, for example aluminum. As a result thereof, the process according to the invention will also be independent of the choice of the pertinent material of the pipe. The radial revolution during the hammering will also permit a bending of the pipe into a spiral.

To carry out the process according to the invention, the proposal is made that an operating ram of a cold shaping tool known per se, be used as a hammer which is provided with a double shape and whose operating stroke is adjustable.

The cold shaping tools known per se serve for the cold reshaping of metal sheets and profiles, thus among other things, for the pressure forging and reshaping of angle sections, for the arching and stretching of pieces of plate, as well as for the smoothing and reshaping of these pieces. These tools have a so-called operating ram which can be shifted or adjusted by hand or electrically in its operating stroke. It is opposed by another ram which has been mounted elastically and which also has a certain operating stroke corresponding thereto which according to the invention, is also supposed to be adjustable. The last mentioned ram, according to a design given by way of example, is called the lower ram" and the operating one is called the upper ram. Corresponding shapes are now attached to both rams which permit the cold bending of a pipe according to the process of the invention.

In a further object of the invention, the proposal is made that the bending radius of the "upper double hammer shape be larger than that of the countershape. This measure will be efficient for the carrying out of the process according to the invention because, as a result thereof, one will create in a simple manner two places located at a distance from one another which will hammer on the supported pipe.

As a further object all lateral edges of the double hammer shape and of the countershape have been provided with radii. This measure will prevent, among other things, a deformation of the cross section of the pipe.

Furthermore it is proposed that the double hammer shape consist of a carrier with hammer inserts. As a result thereof, a considerable possibility for variation of the pipes that are to be formed with regard to their cross section will be achieved. If, for example, light metal pipes are to be bent, then the insertion of shapes made of metal may lead to considerable deformations of the cross section and to damage to the surface. For these cases, the invention proposes that the hammer inserts be made from metal as well as from a plastic, for example, hard rubber or an impact resistant polyester material.

A special design of the arrangement according tothe invention provides for the distance of the hammer inserts to be variable and for the radii of the pipes of the hammer inserts to correspond to half the diameter of the pipe that is to be bent. Furthermore, the proposal is made to select the radius of the pipe of the countershape either equal to or larger than half the diameter of the pipe that is to be bent. By this measure the capacity for application and use of the process according to the invention and of the arrangement for carrying it out will be considerably increased.

Further advantages and objects of the invention will be apparent from the following description when considered in connection with the accompanying drawings in which;

FIG. 1 is a partial section in side view of the apparatus according to the invention,

FIG. 2 shows a partial side view and longitudinal cross section of the apparatus according to the invention as viewed in the direction of the arrow X of FIG. 1,

FIG. 3 is a side view partly in section of a double hammer structure,

FIG. 4 is a side view of a double hammer shape according to FIG. 3, and

FIG. 5 is a side view of the hammer inserts according to FIG. 4.

A cold-shaping tool 10 has two rams l1 and 12. The lower ram 11 serves as a so-called bearing ram, while the upper ram 12 can be designated as the actual operating ram. In a bore 13 of the bearing ram 11, the countershape or anvil 30 has been arranged exchangeably. A spring as a flat curved member 14, whose pre-tension can be varied and fixed by means of an adjusting arrangement 15, imparts a certain operating stroke to the ram 11. The operating stroke 16 of the upper ram 12 is likewise adjustable as a result of an arrangement, not shown. This structure of the tool now serves after attachment of the exchangeable shapes 20, 30, for hammering of the bend in the pipe corresponding to the desired radius. At the same time, the shape 20 of a design given by way of example according to FIG. 2, is developed in such a manner that two hammer elements 21 and 22, arranged at a distance from one another have a bending radius 40, which is larger than the radius 50 of the countershape 30.

The lateral edges 23, 24, 25 and 26, as well as 31 and 32, have been provided with radii, not shown. The carrier 27 of the double hammer shape 20 is exchangeably seated in the upper operating ram 12.

FIG. 3 shows a modified structure of a double hammer shape in which a carrier 127 has been provided with oblong holes 128 in order to be able to shift the hammer inserts 121 and 122 in a guide groove 129, for example a dovetail guide, and thus to make the distance 117 of the two hammer inserts 121 and 122 variable.

In FIGS. 4 and 5, hammer inserts 121 and 122, 221 and 222 have been shown whose radii 160 and 260 respectively, are adapted to the pipe 100 which is to be bent. Depending on the radius of the pipe that is to be bent, theproper hammer inserts can thus be inserted into the bearer 127 according to the invention, and can be fixed by adjusting bolts 118 at a certain distance 1 17 from one another.

If a pipe is to be cold-bent, for example into a circle, then the double hammer shape 20 and the countershape 30 are fastened to the operating rams l2 and 11 respectively, of a cold-shaping tool 10. The operating stroke 16, FIG. 1, of the upper ram 12 will be adjusted according to the bending radius required and the pre-tension of the spring arrangement 14 will be fixed by means of the adjusting screw 15, corresponding to the material of the pipe that is to be bent. lfone operates with a structure according to FIGS. 3, 4 and 5, then the hammer inserts 121 and 122, 221 and 222 can be adapted at the same time as to the specific material used, at a distance 117 from one another and in a radius 160 and 260 to the corresponding conditions of the pipe 100 that is to be bent.

The pipe is placed onto the countershape anvil 30 and while the hammers 121 and 122 act upon the pipe 100 in accordance with the adjusted operating stroke 16 and 116, said pipe after bending will be shifted either automatically or manually and thus the desired bend is formed. With manufacturing models to mention only one example, the required operating stroke 16 and 116 will first have to be ascertained by experimentation. The method according to the invention easily permits a readjustment of the stroke, as well as the pushing, forward and backward of the workpiece, so that corrections in the radii can be carried out without any special the apparatus comprising means for exerting a hammering ac-.

tion on said pipe, said means comprising deforming heads mounted on a reciprocating member and further comprising an anvil, said pipe being adapted to be moved longitudinally between said anvil and said heads during the hammering action with respect to the strokes of said member, said deforming heads and said anvil each having a deforming surface suitable for bending the pipe into a predetermined arch.

2. Apparatus according to claim 1 wherein said anvil is resiliently mounted in the direction of said hammering action.

3. Apparatus according to claim 1 wherein the edges of said deforming heads and said anvil all have the same radii.

4. Apparatus according to claim 1 wherein said deforming heads include a carrier bar and hammer inserts mounted on said bar.

5. Apparatus according to claim 4 wherein said inserts comprise a material selected from the group consisting of metal, plastic, hard rubber, and impact-resistant polyester material.

6. Apparatus according to claim 4 wherein said bar is provided with elongated slots for said inserts so as to permit adjustment thereof toward and away from one another.

7. Apparatus according to claim 1, in which the radn of sald hammer inserts correspond to half the diameter of the radius of the pipe to be bent.

8. Apparatus according to claim'2, characterized in that the radius of said anvil equals at least half the diameter of the pipe which is to be bent. 

1. Apparatus for bending a pipe into a predetermined arch, the apparatus comprising means for exerting a hammering action on said pipe, said means comprising deforming heads mounted on a reciprocating member and further comprising an anvil, said pipe being adapted to be moved longitudinally between said anvil and said heads during the hammering action with respect to the strokes of said member, said deforming heads and said anvil each having a deforming surface suitable for bending the pipe into a predetermined arch.
 2. Apparatus according to claim 1 wherein said anvil is resiliently mounted in the direction of said hammering action.
 3. Apparatus according to claim 1 wherein the edges of said deforming heads and said anvil all have the same radii.
 4. Apparatus according to claim 1 wherein said deforming heads include a carrier bar and hammer inserts mounted on said bar.
 5. Apparatus according to claim 4 wherein said inserts comprise a material selected from the group consisting of metal, plastic, hard rubber, and impact-resistant polyester material.
 6. Apparatus according to claim 4 wherein said bar is provided with elongated slots for said inserts so as to permit adjustment thereof toward and away from one another.
 7. Apparatus according to claim 1, in which the radii of said hammer inserts correspond to half the diameter of the radius of the pipe to be bent.
 8. Apparatus according to claim 2, characterized in that the radius of said anvil equals at least half the diameter of the pipe which is to be bent. 